# coding=utf-8
# --------------------------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for license information.
# --------------------------------------------------------------------------------------------

import asyncio
import sys
import uamqp

from uuid import uuid4
from knack.log import get_logger
from typing import List
from azext_iot.constants import VERSION, USER_AGENT
from azext_iot.monitor.models.target import Target
from azext_iot.monitor.utility import get_loop

logger = get_logger(__name__)
DEBUG = False


def start_single_monitor(
    target: Target,
    enqueued_time_utc,
    on_start_string: str,
    on_message_received,
    timeout=0,
):
    """
    :param on_message_received:
        A callback to process messages as they arrive from the service.
        It takes a single argument, a ~uamqp.message.Message object.
    """
    return start_multiple_monitors(
        targets=[target],
        enqueued_time_utc=enqueued_time_utc,
        on_start_string=on_start_string,
        on_message_received=on_message_received,
        timeout=timeout,
    )


def start_multiple_monitors(
    targets: List[Target],
    on_start_string: str,
    enqueued_time_utc,
    on_message_received,
    timeout=0,
):
    """
    :param on_message_received:
        A callback to process messages as they arrive from the service.
        It takes a single argument, a ~uamqp.message.Message object.
    """
    coroutines = [
        _initiate_event_monitor(
            target=target,
            enqueued_time_utc=enqueued_time_utc,
            on_message_received=on_message_received,
            timeout=timeout,
        )
        for target in targets
    ]

    loop = get_loop()

    future = asyncio.gather(*coroutines, return_exceptions=True)
    result = None

    try:
        print(on_start_string, flush=True)
        future.add_done_callback(lambda _: _stop_and_suppress_eloop(loop))
        result = loop.run_until_complete(future)
    except KeyboardInterrupt:
        print("Stopping event monitor...", flush=True)
        try:
            # TODO: remove when deprecating
            # pylint: disable=no-member
            tasks = asyncio.all_tasks(loop)
            for t in tasks:  # pylint: disable=no-member
                t.cancel()
            loop.run_forever()
        except RuntimeError:
            pass  # no running loop anymore
    finally:
        if result:
            errors = result[0]
            if errors and errors[0]:
                logger.debug(errors)
                raise RuntimeError(errors[0])


async def _initiate_event_monitor(
    target: Target, enqueued_time_utc, on_message_received, timeout=0
):
    if not target.partitions:
        logger.warning("No Event Hub partitions found to listen on.")
        return

    coroutines = []

    async with uamqp.ConnectionAsync(
        target.hostname,
        sasl=target.auth,
        debug=DEBUG,
        container_id=_get_container_id(),
        properties=_get_conn_props(),
    ) as conn:
        for p in target.partitions:
            coroutines.append(
                _monitor_events(
                    target=target,
                    connection=conn,
                    partition=p,
                    enqueued_time_utc=enqueued_time_utc,
                    on_message_received=on_message_received,
                    timeout=timeout,
                )
            )
        return await asyncio.gather(*coroutines, return_exceptions=True)


async def _monitor_events(
    target: Target,
    connection,
    partition,
    enqueued_time_utc,
    on_message_received,
    timeout=0,
):
    source = uamqp.address.Source(
        "amqps://{}/{}/ConsumerGroups/{}/Partitions/{}".format(
            target.hostname, target.path, target.consumer_group, partition
        )
    )
    source.set_filter(
        bytes(
            "amqp.annotation.x-opt-enqueuedtimeutc > " + str(enqueued_time_utc), "utf8"
        )
    )

    exp_cancelled = False
    receive_client = uamqp.ReceiveClientAsync(
        source,
        auth=target.auth,
        timeout=timeout,
        prefetch=0,
        client_name=_get_container_id(),
        debug=DEBUG,
    )

    try:
        if connection:
            await receive_client.open_async(connection=connection)

        async for msg in receive_client.receive_messages_iter_async():
            on_message_received(msg)

    except asyncio.CancelledError:
        exp_cancelled = True
        await receive_client.close_async()
    except uamqp.errors.LinkDetach as ld:
        if isinstance(ld.description, bytes):
            ld.description = str(ld.description, "utf8")
        raise RuntimeError(ld.description)
    except KeyboardInterrupt:
        logger.info("Keyboard interrupt, closing monitor on partition %s", partition)
        exp_cancelled = True
        await receive_client.close_async()
        raise
    finally:
        if not exp_cancelled:
            await receive_client.close_async()
        logger.info("Closed monitor on partition %s", partition)


def _stop_and_suppress_eloop(loop):
    try:
        loop.stop()
    except Exception:
        pass


def _get_conn_props():
    return {
        "product": USER_AGENT,
        "version": VERSION,
        "framework": "Python {}.{}.{}".format(*sys.version_info[0:3]),
        "platform": sys.platform,
    }


def _get_container_id():
    return "{}/{}".format(USER_AGENT, str(uuid4()))